s3 image file validation

backend/config/imageLimits.js

@@ -0,0 +1,13 @@
+/**
+ * Image upload limits configuration
+ * Keep in sync with frontend/src/config/imageLimits.ts
+ */
+const IMAGE_LIMITS = {
+  items: 10,
+  forum: 10,
+  conditionChecks: 10,
+  profile: 1,
+  messages: 1,
+};
+
+module.exports = { IMAGE_LIMITS };